What can happen when medicines are mixed

Nearly all of us at least once a year pop a pill, ingest a liquid, rub on a cream or squeeze some drops seeking relief from what ails us.

But with the promise of an improvement in wellbeing comes the possibility of an undesirable side effect or drug interaction.

Each year, an estimated 1.5 million Australians experience an adverse medicine event, with 190,000 of those admitted to hospital, at a cost to individuals and the community of about $660 million, according to NPS MedicineWise figures.

“The more medicines you are on, the more likely you are going to have interactions and past a certain point it is almost guaranteed,” WA Health Department chief pharmacist Neil Keen said.

Mixing multiple medications, prescription and complementary, as well as alcohol and food can all cause adverse reactions ranging from minor to serious.

Usually they result in either stopping a medicine from working effectively or amplifying the effect of a medicine and subsequently exaggerating the side effects.

Mixing your meds with alcohol can be dangerous, especially for drugs such as sleeping tablets, painkillers and antipsychotics, because it can strengthen the sedation effect of the medicine to potentially dangerous levels. Certain antibiotics, too, can cause a nasty reaction if combined with alcohol.

Complementary medicines can be another culprit for adverse events, so people should not be fooled into thinking they were safe just because they were “natural”, according to NPS MedicineWise phone line services manager Sarah Spagnardi.

“We get calls about that every day, where people have made a decision to take a complementary or alternative product and they get home and are concerned about whether it might interact with their other medicines or they take them and then find out they have experienced a potential interaction or side effect,” she said.

“It is important for people to know what the active ingredient or ingredients are in all of their medicines, whether they are medicines prescribed by the doctor or something they might purchase outside the pharmacy at the supermarket or the health food shop, because there are ingredients in some complementary products that do cause (effects such as) sedation.

“We know that some people are reticent to tell their GP that they are taking complementary products but that can be a recipe for disaster, especially for products bought online where the actual ingredient may not be known.

“There is an absolute belief I think among some people that natural means safer and that is certainly not always the case,” she said.

A number of complementary medicines are known to interact with prescribed medicines, one of which is St John’s wort, a herbal remedy often used to treat mild to moderate depression.

“We know absolutely that St John’s wort can lessen the effectiveness of the contraceptive pill and that is not something that people might be widely aware of, particularly if they are purchasing that product outside of the environment where they have access to a health professional who is going to ask those questions.”

The effects of prescription antidepressants will be exaggerated by St John’s wort.

Other known complementary medicine interactions include black cohosh — used to treat various conditions including menopause symptoms — which is believed to interact with some conventional medications, including chemotherapy drugs and the cholesterol-lowering drug atorvastatin.

Glucosamine and ginkgo interact with a number of medications, including blood-thinning drug warfarin, increasing the risk of bleeding.

Grapefruit is known to increase the amount of active ingredient in some medicines available to the body through a complex enzyme reaction.Generally medicines that react with grapefruit, such as warfarin, carry specific warnings on the product packaging.

Warnings can also relate to when a product should be taken in relation with food, usually to avoid stomach irritation or nausea and to maximise the benefit of the medication.

“There might also be specific warnings about things like calcium in dairy products and the need to space those out by two hours or more. Those issues are highlighted because some medicines will join up and bind with the calcium and become inactive,” Mr Keen said.

“If you are thinking you are suffering from a side effect, get help quickly. Depending on the severity, the usual advice is don’t stop something but find out what to do.

Side effects are very common and in most cases they are fairly treatable.” .

Consumer medical information on all prescription and some over-the-counter medications is available at nps.org.au/medicines.

How we take our doses

Nearly everyone — 95 per cent in a 2012 NPS MedicineWise survey — takes some form of medication over the course of a year. Of these, 68 per cent had taken prescription-based medicines, 76 per cent over-the-counter pain relief medication, 52 per cent other over the counter medicines such as eye drops, cold and flu tablets or nasal sprays for hay fever, and 56 per cent a vitamin, mineral or herbal supplement.

One in five people experienced an adverse effect from their medicine in the previous 12 months, including nausea, vomiting, diarrhoea and fatigue.

Fifty-seven per cent admitted they had made a mistake with their medicines in the past 12 months.

One in five had taken an out-of-date or expired medicine.

Just under half had missed a dose of their medicine.

One in four had taken medicine without food even though it was meant to be taken with food.

One in four older people find it hard to remember to take some of their medicines.

One in three older people do not always read the labels.

Just 45 per cent of older people always read the consumer medicine information when they start a new medicine.

One in four people over 65 think that prescription medicines rarely (19 per cent) or never (7 per cent) have side effects. Only 21 per cent knew that it was common for medicines to have side effects.

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